JP7521399B2 - Image forming device - Google Patents

Description

The present invention relates to an image forming device.

In electrophotographic image forming devices such as copiers and printers, a device is widely used that develops an electrostatic latent image formed on the surface of a photosensitive drum, which is an image carrier, with a developer to form a toner image that is later transferred to paper. An example of such a conventional image forming device is disclosed in Patent Document 1.

The conventional image forming apparatus disclosed in Patent Document 1 includes a first toner container and a second toner container that contain toner to be replenished to one developing device. When one of the toner containers becomes empty, this image forming apparatus is capable of replenishing toner from the other toner container to the developing device. This reduces the frequency and duration of image forming operation stoppages due to toner container replacement.

JP 2019-109326 A

The conventional image forming device described above has two sensors for detecting the presence or absence of toner: one in the toner transport section from the first toner container to the developing device, and one in the toner transport section from the second toner container to the developing device. The inclusion of two sensors poses the problem of increased costs and size of the image forming device.

The present invention has been made in consideration of the above points, and aims to provide an image forming device that is low-cost and compact, and can accurately detect the remaining amount of toner in each of two containers that supply toner to one developing device.

In order to solve the above problem, the image forming apparatus of the present invention includes a developing device, a first container, a second container, a toner supply device, and a remaining amount detection unit. The developing device supplies toner to an image carrier. The first container and the second container store the toner to be supplied to the developing device. The toner supply device supplies the toner from the first container and the second container to the developing device. The remaining amount detection unit detects the remaining amount of the toner in the first container and the second container. The toner supply device includes a supply pipe, a first conveying pipe, a second conveying pipe, a first conveying member, a second conveying member, a clutch, a first detection shaft, a second detection shaft, and an optical sensor. The supply pipe is single and connected to the developing device, and the toner flows into the developing device. The first conveying pipe is connected between the first container and the supply pipe, and the toner is transported from the first container side toward the supply pipe side. The second transport pipe is connected between the second container and the supply pipe, and transports the toner from the second container side toward the supply pipe side. The first transport member is rotatably disposed in the first transport pipe, and transports the toner from the first container side toward the supply pipe side. The second transport member is rotatably disposed in the second transport pipe, and transports the toner from the second container side toward the supply pipe side. The clutch selectively drives one of the first transport member and the second transport member. The first detection shaft is connected to the first transport member and rotates together with the first transport member. The second detection shaft is connected to the second transport member and rotates together with the second transport member. The optical sensor is a single sensor and detects the rotation of the first detection shaft and the second detection shaft. The remaining amount detection unit counts the number of rotations of the first detection shaft and the second detection shaft based on an output signal from the optical sensor, and detects the remaining amount of the toner in the first container and the second container based on the number of rotations. The first detection axis has a first light-shielding plate that moves into and out of the optical path of the optical sensor. The second detection axis has a second light-shielding plate that moves into and out of the optical path of the optical sensor. One of the first light-shielding plate and the second light-shielding plate rotates with the first conveying member or the second conveying member driven by the clutch and comes into contact with the other, thereby removing the other from the optical path of the optical sensor.

According to the configuration of the present invention, either the first light shielding plate or the second light shielding plate is present on the optical path of the optical sensor. In other words, a single optical sensor can detect the rotation of each of the first light shielding plate and the second light shielding plate individually. This makes it possible to accurately detect the remaining amount of toner in each of the two containers that supply toner to one developing device with a configuration that is low cost and compact.

1 is a schematic cross-sectional view illustrating a configuration of an image forming apparatus according to an embodiment of the present invention. FIG. 2 is a block diagram showing a schematic configuration of the image forming apparatus shown in FIG. 1 . FIG. 2 is a cross-sectional view showing the periphery of an image forming unit of the image forming apparatus shown in FIG. 1 . FIG. 2 is a perspective view of the periphery of a toner supply device of the image forming apparatus of FIG. 1 . FIG. 5 is a front view of the toner supply device and its periphery shown in FIG. 4 . FIG. 5 is a side view of the toner supply device and its periphery shown in FIG. 4 . FIG. 5 is a perspective view of the toner supply device of FIG. 4 . FIG. 5 is a plan view of the toner supply device of FIG. 4 . 8 is a perspective view of a first conveying pipe and a second conveying pipe of the toner supply device of FIG. 7. 10 is a perspective view of a first transport member and a second transport member of the toner supply device of FIG. 9 . 10 is a side view of a first conveying pipe and a second conveying pipe of the toner supply device of FIG. 9 . 10 is a rear cross-sectional view of the first detection shaft, the second detection shaft, and the optical sensor of the toner supply device of FIG. 9 . FIG. 13 is an explanatory diagram showing a rotation state of a first detection axis and a second detection axis in FIG. 12 . FIG. 13 is an explanatory diagram showing a rotation state of a first detection axis and a second detection axis in FIG. 12 . FIG. 13 is an explanatory diagram showing a rotation state of a first detection axis and a second detection axis in FIG. 12 . FIG. 13 is an explanatory diagram showing a detailed configuration of a first detection axis and a second detection axis in FIG. 12 . 3 is an explanatory diagram relating to counting of the number of rotations of a first detection axis and a second detection axis by the remaining amount detection unit of FIG. 2 . FIG.

The following describes an embodiment of the present invention with reference to the drawings. Note that the present invention is not limited to the following contents.

Figure 1 is a schematic cross-sectional view showing the configuration of an image forming apparatus 1 according to an embodiment. Figure 2 is a block diagram showing the schematic configuration of the image forming apparatus 1 of Figure 1. Figure 3 is a cross-sectional view showing the periphery of the image forming unit 20 of the image forming apparatus 1 of Figure 1. One example of the image forming apparatus 1 according to this embodiment is a tandem type color printer that transfers a toner image to paper S using an intermediate transfer belt 31. The image forming apparatus 1 may be a so-called multifunction machine equipped with functions such as printing, scanning (image reading), and facsimile transmission.

As shown in Figures 1, 2 and 3, the image forming device 1 has a paper feed section 3, a paper transport section 4, an exposure section 5, an image forming section 20, a transfer section 30, a fixing section 6, a paper discharge section 7 and a control section 8, which are provided in the main body 2.

The paper feed unit 3 stores multiple sheets of paper S, and separates and sends out the sheets S one by one during printing. The paper transport unit 4 transports the paper S sent out from the paper feed unit 3 to the secondary transfer unit 33 and the fixing unit 6, and then discharges the paper S after fixing from the paper discharge port 4a to the paper discharge unit 7. When double-sided printing is performed, the paper transport unit 4 distributes the paper S after fixing of the first side to the reversal transport unit 4c by the branch unit 4b, and transports the paper S again to the secondary transfer unit 33 and the fixing unit 6. The exposure unit 5 irradiates the image forming unit 20 with laser light controlled based on image data.

The image forming units 20 are disposed below the intermediate transfer belt 31. The image forming units 20 include an image forming unit 20Y for yellow, an image forming unit 20C for cyan, an image forming unit 20M for magenta, and an image forming unit 20B for black. These four image forming units 20 have the same basic configuration. For this reason, in the following description, the identification symbols "Y", "C", "M", and "B" representing each color may be omitted unless there is a particular need to limit it.

As shown in FIG. 3, the image forming unit 20 includes a photoconductor drum (image carrier) 21 that is supported so as to be rotatable in a predetermined direction (clockwise in FIG. 3). The image forming unit 20 further includes a charging unit 22, a developing device 40, and a drum cleaning unit 23 that are arranged around the photoconductor drum 21 in the direction of its rotation. A primary transfer unit 32 is arranged between the developing device 40 and the drum cleaning unit 23.

The photosensitive drum 21 has a photosensitive layer on its outer circumferential surface. The charging section 22 charges the outer circumferential surface of the photosensitive drum 21 to a predetermined potential. The exposure section 5 exposes the outer circumferential surface of the photosensitive drum 21 charged by the charging section 22 to light, forming an electrostatic latent image of the original image on the outer circumferential surface of the photosensitive drum 21. The developing device 40 develops the electrostatic latent image by attaching toner to it, forming a toner image. Each of the four image forming sections 20 forms a toner image of a different color. The drum cleaning section 23 removes and cleans toner remaining on the outer circumferential surface of the photosensitive drum 21 after the toner image has been primarily transferred to the outer circumferential surface of the intermediate transfer belt 31. In this way, the image forming section 20 forms an image on the paper S.

As shown in FIG. 1, the transfer unit 30 includes an intermediate transfer belt 31, primary transfer units 32Y, 32C, 32M, and 32B, a secondary transfer unit 33, and a belt cleaning unit 34. The intermediate transfer belt 31 is disposed above the four image forming units 20. The intermediate transfer belt 31 is supported so as to be rotatable in a predetermined direction (counterclockwise in FIG. 1), and is an intermediate transfer body onto which the toner images formed in each of the four image forming units 20 are sequentially superimposed and primarily transferred. The four image forming units 20 are disposed in a line from the upstream side to the downstream side in the rotation direction of the intermediate transfer belt 31 in a so-called tandem system.

The primary transfer units 32Y, 32C, 32M, and 32B are disposed above the image forming units 20Y, 20C, 20M, and 20B of each color, sandwiching the intermediate transfer belt 31. The secondary transfer unit 33 is disposed upstream of the fixing unit 6 in the paper transport direction of the paper transport unit 4, and downstream of the image forming units 20Y, 20C, 20M, and 20B of each color in the rotation direction of the intermediate transfer belt 31 of the transfer unit 30. The belt cleaning unit 34 is disposed upstream of the image forming units 20Y, 20C, 20M, and 20B of each color in the rotation direction of the intermediate transfer belt 31.

The toner images are primarily transferred to the outer circumferential surface of the intermediate transfer belt 31 at the primary transfer units 32Y, 32C, 32M, and 32B for each color. Then, as the intermediate transfer belt 31 rotates, the toner images of the four image forming units 20 are continuously superimposed and transferred to the intermediate transfer belt 31 at a predetermined timing, forming a color toner image on the outer circumferential surface of the intermediate transfer belt 31 in which the toner images of the four colors, yellow, cyan, magenta, and black, are superimposed.

The color toner image on the outer surface of the intermediate transfer belt 31 is transferred to the paper S, which is sent in sync by the paper transport unit 4, at a secondary transfer nip formed in the secondary transfer unit 33. The belt cleaning unit 34 removes and cleans the toner remaining on the outer surface of the intermediate transfer belt 31 after the secondary transfer.

The fixing unit 6 is disposed above the secondary transfer unit 33. The fixing unit 6 heats and presses the paper S onto which the toner image has been transferred, thereby fixing the toner image to the paper S.

The paper discharge section 7 is located above the transfer section 30. After the toner image has been fixed and printing is complete, the paper S is transported to the paper discharge section 7.

The control unit 8 includes a CPU, an image processing unit, a memory unit, and other electronic circuits and electronic components (all not shown). The CPU controls the operation of each component provided in the image forming device 1 based on control programs and data stored in the memory unit to perform processing related to the functions of the image forming device 1. The paper feed unit 3, paper transport unit 4, exposure unit 5, image forming unit 20, transfer unit 30, and fixing unit 6 each receive individual commands from the control unit 8 and work together to print on the paper S. The memory unit is composed of a combination of a non-volatile storage device such as a program ROM (Read Only Memory) or a data ROM, and a volatile storage device such as a RAM (Random Access Memory).

Next, the configuration of the developing device 40 and its surroundings will be described with reference to FIG. 3. Note that since the developing devices 40 for each color have the same basic configuration, the identification symbols representing each color and their explanations will be omitted.

The developing device 40 supplies toner to the outer peripheral surface of the photoconductor drum 21. The developing device 40 includes a developing container 41, a first agitating and transporting member 42, a second agitating and transporting member 43, a developing roller 44, and a regulating member 45.

The developing container 41 has an elongated shape that extends along the axial direction of the photosensitive drum 21 (the depth direction of the paper in FIG. 3) and is arranged with its longitudinal direction horizontal. The developing container 41 contains, as the developer, a magnetic one-component developer that contains, for example, magnetic toner. The developer may be, for example, a non-magnetic one-component developer or a two-component developer that contains toner and a magnetic carrier. The developing container 41 has a partition section 411, a first transport chamber 412, and a second transport chamber 413.

The partition 411 is provided at the bottom inside the developing container 41. The partition 411 is provided at approximately the center of the bottom of the developing container 41 in a direction intersecting the axial direction (left-right direction in FIG. 3), and extends in the axial direction and up-down direction. The partition 411 divides the inside of the developing container 41 in a direction intersecting the axial direction (left-right direction in FIG. 3). The developing container 41 has communication parts (not shown) between the first transport chamber 412 and the second transport chamber 413 on both ends of the partition 411 in the axial direction (depth direction of the paper in FIG. 3).

The first transport chamber 412 and the second transport chamber 413 are provided inside the developing container 41. The first transport chamber 412 and the second transport chamber 413 are formed by dividing the inside of the developing container 41 by a partition 411, and are arranged side by side. The second transport chamber 413 is arranged adjacent to and below the area where the developing roller 44 is arranged inside the developing container 41. The first transport chamber 412 is arranged in an area inside the developing container 41 that is farther away from the developing roller 44 than the second transport chamber 413. The first transport chamber 412 receives toner replenishment via a replenishment pipe connection part 412a shown in FIG. 3.

The first agitation and transport member 42 is disposed inside the first transport chamber 412. The second agitation and transport member 43 is disposed inside the second transport chamber 413. The second agitation and transport member 43 extends parallel to and close to the developing roller 44. The first agitation and transport member 42 and the second agitation and transport member 43 are supported by the developing container 41 so as to be rotatable about an axis extending parallel to the photosensitive drum 21. The first agitation and transport member 42 and the second agitation and transport member 43 rotate about their axes, thereby agitating and transporting the developer in opposite directions along the axial direction of the rotation.

By rotating the first agitating and conveying member 42 and the second agitating and conveying member 43, the developer circulates between the first conveying chamber 412 and the second conveying chamber 413 through the communication parts arranged at both ends of the partition part 411 in the axial direction. In the first conveying chamber 412 and the second conveying chamber 413, the toner supplied from the outside is agitated and charged.

The developing roller 44 is disposed above the second stirring and transporting member 43 inside the developing container 41. The developing roller 44 is supported by the developing container 41 so as to be rotatable about an axis extending parallel to the axis of the photosensitive drum 21. The developing roller 44 has, for example, a cylindrical developing sleeve that rotates counterclockwise in FIG. 3, and a developing roller-side magnetic pole fixed within the developing sleeve (neither shown).

The developing roller 44 has a portion of its outer circumferential surface exposed from the developing container 41, and faces and is close to the photosensitive drum 21. The developing roller 44 carries toner on its outer circumferential surface in the facing area with the photosensitive drum 21 to supply to the outer circumferential surface of the photosensitive drum 21. The developing roller 44 adheres the toner in the second transport chamber 413 to the electrostatic latent image on the outer circumferential surface of the photosensitive drum 21 to form a toner image.

The regulating member 45 is disposed upstream of the rotation direction of the developing roller 44 in the opposing region between the developing roller 44 and the photosensitive drum 21. The regulating member 45 is disposed closely opposite the developing roller 44 with a predetermined gap between its tip and the outer peripheral surface of the developing roller 44. The regulating member 45 extends over the entire area in the axial direction of the developing roller 44 (the depth direction of the paper in FIG. 3). The regulating member 45 regulates the layer thickness of the developer (toner) carried on the outer peripheral surface of the developing roller 44.

The toner in the developing container 41 is stirred, circulated and charged in the first stirring and transporting member 42 and the second stirring and transporting member 43, and is delivered to the outer circumferential surface of the developing roller 44 by the second stirring and transporting member 43. After the layer thickness of the toner is regulated by the regulating member 45, the toner is transported to the opposing area between the developing roller 44 and the photosensitive drum 21 by the rotation of the developing roller 44. When a predetermined developing voltage is applied to the developing roller 44, the toner carried on the outer circumferential surface of the developing roller 44 flies to the outer circumferential surface of the photosensitive drum 21 in the developing space due to the potential difference with the potential of the outer circumferential surface of the photosensitive drum 21, and the electrostatic latent image on the outer circumferential surface of the photosensitive drum 21 is developed.

To supply toner to the developing device 40, the image forming device 1 is provided with a first container 51, a second container 52, and a toner supply device 60 (see FIG. 4). The first container 51, the second container 52, and the toner supply device 60 are disposed above the developing device 40. The first container 51, the second container 52, and the toner supply device 60 are provided one each for each of the four colors: yellow, cyan, magenta, and black.

Next, the configuration of the toner supply device 60 and its surroundings will be described with reference to Figures 4 to 12. Figure 4 is a perspective view of the toner supply device 60 and its surroundings of the image forming apparatus 1 of Figure 1. Figure 5 is a front view of the toner supply device 60 and its surroundings of Figure 4. Figure 6 is a side view of the toner supply device 60 and its surroundings of Figure 4. Figure 7 is a perspective view of the toner supply device 60 of Figure 4. Figure 8 is a plan view of the toner supply device 60 of Figure 4. Figure 9 is a perspective view of the first conveying tube 66 and the second conveying tube 67 of the toner supply device 60 of Figure 7. Figure 10 is a perspective view of the first conveying member 68 and the second conveying member 69 of the toner supply device 60 of Figure 9. Figure 11 is a side view of the first conveying tube 66 and the second conveying tube 67 of the toner supply device 60 of Figure 9. Figure 12 is a rear cross-sectional view of the first detection shaft 81, the second detection shaft 82, and the optical sensor 83 and their surroundings of the toner supply device 60 of Figure 9.

The first container 51, the second container 52, and the toner supply device 60 include a first container 51Y, a second container 52Y, and a toner supply device 60Y for yellow, a first container 51C, a second container 52C, and a toner supply device 60C for cyan, a first container 51M, a second container 52M, and a toner supply device 60M for magenta, and a first container 51B, a second container 52B, and a toner supply device 60B for black. The first container 51, the second container 52, and the toner supply device 60 for each of these colors have the same basic configuration. Therefore, in the following description, the identification symbols "Y", "C", "M", and "B" representing each color may be omitted unless there is a need to specifically limit it.

The first container 51 is disposed above the second container 52. The second container 52 is disposed below the first container 51. When viewed from the front, the first container 51 and the second container 52 are disposed offset in the arrangement direction of the image forming unit 20 and the toner supply device 60. The first container 51 and the second container 52 are detachable from the main body 2, and store the toner to be supplied to the developing device 40.

The first container 51 and the second container 52 are elongated cylindrical shapes extending along the axial direction Dx of the photosensitive drum 21, and are arranged with their longitudinal direction horizontal. The peripheral walls of the first container 51 and the second container 52 are formed with spiral protrusions 51s, 52s that protrude radially inward and extend in the longitudinal direction.

The first container 51 and the second container 52 are closed at one end (front side) in the axial direction Dx and have an opening (not shown) at the other end (rear side). The first container 51 and the second container 52 are connected to a first container connection part 61 and a second container connection part 62 of the toner supply device 60 at the open rear side. The first container 51 and the second container 52 are supported by the toner supply device 60 so as to be rotatable around an axis extending parallel to the axial direction Dx of the photosensitive drum 21.

The first container 51 and the second container 52 are rotated by a drive unit (not shown) about an axis extending parallel to the axial direction Dx of the photoconductor drum 21. When the first container 51 and the second container 52 rotate, the toner inside is sent toward the rear side, which is the opening side, by the spiral protrusions 51s, 52s. As a result, the toner inside each of the first container 51 and the second container 52 flows into the toner supply device 60 from the opening.

The toner supply device 60 is disposed behind the first container 51 and the second container 52. The four toner supply devices 60 are arranged in a row in the same order as the four image forming units 20. The toner supply device 60 supplies the toner from the first container 51 and the second container 52 to the developing device 40.

The toner supply device 60 includes a first container connection portion 61, a second container connection portion 62, a supply pipe 63, a first vertical pipe 64, a second vertical pipe 65, a first conveying pipe 66, a second conveying pipe 67, a first conveying member 68, a second conveying member 69, a conveying drive portion 70, a first detection shaft 81, a second detection shaft 82, and an optical sensor 83.

The first container connection part 61 is located at the top of the toner supply device 60, and is located above the second container connection part 62. The first container connection part 61 has a toner flow passage (not shown) therein. The opening side of the first container 51 is connected to the first container connection part 61, and rotatably supports the first container 51. The downstream end of the first container connection part 61 in the toner flow direction is connected to the first vertical pipe 64. When the toner in the first container 51 is supplied to the developing device 40, the toner flows from the first container 51 into the first container connection part 61, passes through the first container connection part 61, and flows out toward the first vertical pipe 64.

The second container connection part 62 is located at the top of the toner supply device 60 and is lower than the first container connection part 61. The second container connection part 62 has a toner flow passage (not shown) therein. The opening side of the second container 52 is connected to the second container connection part 62, and supports the second container 52 so that it can rotate. The downstream end of the second container connection part 62 in the toner flow direction is connected to the second vertical pipe 65. When the toner in the second container 52 is supplied to the developing device 40, the toner flows from the second container 52 into the second container connection part 62 and flows out toward the second vertical pipe 65 through the second container connection part 62.

The supply pipe 63 is disposed at the bottom of the toner supply device 60. The toner supply device 60 includes a single supply pipe 63. The supply pipe 63 is formed in a cylindrical shape extending in the vertical direction. The upper end of the supply pipe 63 is connected to the junction 60a of the first conveying pipe 66 and the second conveying pipe 67. The lower end of the supply pipe 63 is connected to the supply pipe connection portion 412a of the developing device 40. When the toner in the first container 51 and the second container 52 is replenished to the developing device 40, the toner flows from the junction 60a into the supply pipe 63, and then flows through the supply pipe 63 into the developing device 40.

The first vertical pipe 64 is disposed between the first container connection part 61 and the first conveying pipe 66. The first vertical pipe 64 is formed in a cylindrical shape extending in the vertical direction. The upper end of the first vertical pipe 64 is connected to the first container connection part 61. The lower end of the first vertical pipe 64 is connected to the first conveying pipe 66. When the toner in the first container 51 is replenished to the developing device 40, the toner flows from the first container connection part 61 into the first vertical pipe 64, passes through the first vertical pipe 64, and flows out toward the first conveying pipe 66.

The second vertical pipe 65 is disposed between the second container connection part 62 and the second conveying pipe 67. The second vertical pipe 65 is formed in a cylindrical shape extending in the vertical direction. The upper end of the second vertical pipe 65 is connected to the second container connection part 62. The lower end of the second vertical pipe 65 is connected to the second conveying pipe 67. When the toner in the second container 52 is replenished to the developing device 40, the toner flows from the second container connection part 62 into the second vertical pipe 65 and flows out toward the second conveying pipe 67 through the second vertical pipe 65.

The first container 51 and the first container connection part 61 are disposed above the second container 52 and the second container connection part 62, so that the first vertical tube 64 is longer in the vertical direction than the second vertical tube 65. The second container 52 and the second container connection part 62 are disposed below the first container 51 and the first container connection part 61, so that the second vertical tube 65 is shorter in the vertical direction than the first vertical tube 64. The first vertical tube 64 and the second vertical tube 65 are disposed at the same position in the axial direction Dx of the photoconductor drum 21. In other words, the first vertical tube 64 and the second vertical tube 65 are arranged side by side on a straight line perpendicular to the axial direction Dx.

The first conveying pipe 66 is disposed between the first vertical pipe 64 and the supply pipe 63 in the vertical direction. The first conveying pipe 66 is formed in a cylindrical shape extending in the horizontal direction. The first vertical pipe 64 is connected to one end side of the extension direction of the first conveying pipe 66. The other end side of the extension direction of the first conveying pipe 66 is connected to the junction 60a. When the toner in the first container 51 is replenished to the developing device 40, the toner flows from the first vertical pipe 64 into the first conveying pipe 66, passes through the first conveying pipe 66, and flows out toward the junction 60a. In other words, the first conveying pipe 66 is connected between the first container 51 and the supply pipe 63, and the toner is conveyed from the first container 51 side toward the supply pipe 63 side.

The second conveying pipe 67 is disposed between the second vertical pipe 65 and the supply pipe 63 in the vertical direction. The second conveying pipe 67 is formed in a cylindrical shape extending in the horizontal direction. The second vertical pipe 65 is connected to one end of the second conveying pipe 67 in the extension direction. The other end of the second conveying pipe 67 in the extension direction is connected to the junction 60a. When the toner in the second container 52 is replenished to the developing device 40, the toner flows from the second vertical pipe 65 into the second conveying pipe 67 and flows through the second conveying pipe 67 toward the junction 60a. In other words, the second conveying pipe 67 is connected between the second container 52 and the supply pipe 63, and the toner is conveyed from the second container 52 side toward the supply pipe 63 side.

The first conveying pipe 66 and the second conveying pipe 67 are arranged so that their extension lines intersect at the junction 60a of their respective extension directions. In other words, the angle between the first conveying pipe 66 and the second conveying pipe 67 in the horizontal direction is an acute angle, and they are arranged in a V shape when viewed from above and below.

The first conveying member 68 is disposed within the first conveying pipe 66. The first conveying member 68 has a rotating shaft 681 provided between both axial ends of the cylindrical first conveying pipe 66, and a first conveying blade 682 formed on the outer circumferential surface of the rotating shaft 681 and extending in a spiral shape along the axial direction. The first conveying member 68 is supported within the first conveying pipe 66 so as to be rotatable about an axis extending in the horizontal direction. One axial end of the first conveying member 68 is located within the confluence 60a.

The first transport member 68 rotates about its axis to transport the toner in the first transport tube 66 while stirring it along a toner transport direction f1 (see Figures 8, 9, and 10) parallel to the rotation axis. The first transport member 68 transports the toner in the first transport tube 66 from the first vertical tube 64 side toward the junction 60a side. In other words, the first transport member 68 transports the toner from the first container 51 side toward the supply tube 63 side.

The second conveying member 69 is disposed within the second conveying pipe 67. The second conveying member 69 has a rotating shaft 691 provided between both axial ends of the cylindrical second conveying pipe 67, and a second conveying blade 692 formed on the outer circumferential surface of the rotating shaft 691 and extending in a spiral shape along the axial direction. The second conveying member 69 is supported within the second conveying pipe 67 so as to be rotatable about an axis extending horizontally. One axial end of the second conveying member 69 is located within the confluence 60a.

The second transport member 69 rotates about its axis to transport the toner in the second transport tube 67 while stirring it along a toner transport direction f2 (see Figures 8, 9, and 10) parallel to the rotation axis. The second transport member 69 transports the toner in the second transport tube 67 from the second vertical tube 65 side toward the junction 60a side. In other words, the second transport member 69 transports the toner from the second container 52 side toward the supply tube 63 side.

The transport drive unit 70 is disposed at the rear of the toner supply device 60, upstream of the first transport tube 66 and the second transport tube 67 in the toner transport direction. The transport drive unit 70 generates and transmits the driving force that rotates the first transport member 68 and the second transport member 69. The transport drive unit 70 includes a motor 71, a group of gears 72, a first clutch 73, and a second clutch 74.

The motor 71 is connected to the gear group 72. The motor 71 generates a driving force that rotates the first conveying member 68 and the second conveying member 69. The driving force of the motor 71 is transmitted to the first conveying member 68 and the second conveying member 69 via the gear group 72. The motor 71 is controlled by the control unit 8.

The gear group 72 is connected to the motor 71 and the first and second conveying members 68 and 69. The gear group 72 is composed of multiple gears and transmits the driving force of the motor 71 to the first and second conveying members 68 and 69.

The first clutch 73 is disposed on the path of transmission of the driving force from the gear group 72 to the first transport member 68. The first clutch 73 is, for example, a one-way clutch, and allows the first transport member 68 to rotate forward to transport toner along the toner transport direction f1, and restricts reverse rotation.

The second clutch 74 is disposed on the path of transmission of the driving force from the gear group 72 to the second transport member 69. The second clutch 74 is, for example, a one-way clutch, and allows the second transport member 69 to rotate forward to transport toner along the toner transport direction f2, and restricts reverse rotation.

The first clutch 73 and the second clutch 74 selectively drive one of the first transport member 68 and the second transport member 69. That is, in the transport drive unit 70, when the motor 71 rotates in the first direction, the first transport member 68 rotates forward to transport toner along the toner transport direction f1, and the second transport member 69 stops rotating. In addition, in the transport drive unit 70, when the motor 71 rotates in the second direction, the second transport member 69 rotates forward to transport toner along the toner transport direction f2, and the first transport member 68 stops rotating.

The first detection shaft 81 is connected to one of the gears that make up the gear group 72. The first detection shaft 81 is connected to the first transport member 68 via the gear group 72 and rotates together with the first transport member 68. The first detection shaft 81 rotates in the same direction and at the same rotational speed as the first transport member 68. As shown in FIG. 12, the first detection shaft 81 rotates clockwise when viewed from the upstream side of the toner transport direction of the first transport tube 66. In this embodiment, the first detection shaft 81 is adjacent to the second detection shaft 82 and extends parallel to the second detection shaft 82.

The first detection shaft 81 has two first light shielding plates 811. The two first light shielding plates 811 extend radially outward from the first detection shaft 81 and are arranged at angular intervals of 180 degrees in the circumferential direction. As the first detection shaft 81 rotates, the first light shielding plates 811 move in and out of the optical path of the optical sensor 83.

In this embodiment, the second detection shaft 82 is connected coaxially with the rotation shaft 691 of the second transport member 69. That is, the second detection shaft 82 is connected to the second transport member 69 and rotates together with the second transport member 69. The second detection shaft 82 rotates in the same direction and at the same rotational speed as the second transport member 69. As shown in FIG. 12, the second detection shaft 82 rotates counterclockwise when viewed from the upstream side of the toner transport direction of the second transport tube 67.

The second detection shaft 82 has two second light shielding plates 821. The two second light shielding plates 821 extend radially outward from the second detection shaft 82 and are arranged at angular intervals of 180 degrees in the circumferential direction. As the second detection shaft 82 rotates, the second light shielding plates 821 move in and out of the optical path of the optical sensor 83.

The optical sensor 83 is disposed above and between the first detection axis 81 and the second detection axis 82. The toner supply device 60 includes a single optical sensor 83. The optical sensor 83 is, for example, a light-transmitting sensor that includes a light-emitting section and a light-receiving section (both not shown) and has an optical path from the light-emitting section to the light-receiving section. The optical sensor 83 detects the blocking (light blocking) and unblocking (light transmission) of the optical path.

The first light shielding plate 811 of the first detection axis 81 and the second light shielding plate 821 of the second detection axis 82 move in and out of the optical path of the optical sensor 83. This allows the optical sensor 83 to detect the rotation of the first detection axis 81 and the second detection axis 82. The optical sensor 83 outputs a signal related to the detection of the rotation of the first detection axis 81 and the second detection axis 82 to the control unit 8.

The control unit 8 receives an output signal from the optical sensor 83. The control unit 8 has a remaining amount detection unit 8a shown in FIG. 2. The remaining amount detection unit 8a is realized in software by the CPU's calculation processing according to a program stored in the storage unit. The remaining amount detection unit 8a may also be formed by an electrical hardware circuit.

The remaining amount detection unit 8a detects the remaining amount of toner in the first container 51 and the second container 52 based on the output signal of the optical sensor 83. In detail, the remaining amount detection unit 8a counts the number of rotations of the first detection shaft 81 and the second detection shaft 82 based on the output signal from the optical sensor 83, and detects the remaining amount of toner in the first container 51 and the second container 52 based on the number of rotations.

Next, the detailed configuration of the first detection axis 81, the second detection axis 82, and the optical sensor 83 will be described using Figs. 13 to 16 in addition to Fig. 12. Figs. 13, 14, and 15 are explanatory diagrams showing the rotational state of the first detection axis 81 and the second detection axis 82 in Fig. 12. Fig. 16 is an explanatory diagram showing the detailed configuration of the first detection axis 81 and the second detection axis 82 in Fig. 12.

When the toner in the first container 51 becomes empty, for example, the image forming device 1 can replenish the developing device 40 with toner from the second container 52. The remaining amount detection unit 8a counts the number of rotations of the first detection shaft 81 based on the output signal from the optical sensor 83, and detects that the toner in the first container 51 has become empty based on the number of rotations. The control unit 8 controls the motor 71 to stop the rotation of the first conveying member 68, and stops the replenishment of toner from the first container 51.

For example, when the toner in the first container 51 becomes empty, the first detection shaft 81 may stop rotating, as shown in FIG. 13. According to FIG. 13, the first light shielding plate 811 of the first detection shaft 81 is located on the optical path of the optical sensor 83 and blocks the optical path.

Next, the control unit 8 controls the motor 71 to start the rotation of the second transport member 69, and starts the supply of toner from the second container 52. This causes the second detection shaft 82 to rotate together with the second transport member 69. Then, as shown in FIG. 14, the second light shielding plate 821 of the second detection shaft 82 comes into contact with the first light shielding plate 811 on the optical path of the optical sensor 83.

Furthermore, when the second detection axis 82 rotates, as shown in FIG. 15, the second light shielding plate 821 pushes aside the first light shielding plate 811, causing the first light shielding plate 811 to retreat from the optical path of the optical sensor 83. The first light shielding plate 811 retreats outside the rotation area of the second light shielding plate 821 (inside the two-dot chain circle in FIG. 15) and is not detected by the optical sensor 83.

In addition, the image forming device 1 can replenish toner from the first container 51 to the developing device 40 when, for example, the toner in the second container 52 becomes empty. As described above, when the second light shielding plate 821 is present on the optical path of the optical sensor 83, the first light shielding plate 811 contacts and pushes the second light shielding plate 821 aside, causing the second light shielding plate 821 to move away from the optical path of the optical sensor 83.

In this way, one of the first light shielding plate 811 and the second light shielding plate 821 rotates together with the first conveying member 68 or the second conveying member 69 driven by the first clutch 73 and the second clutch 74, respectively, and comes into contact with the other, thereby removing the other from the optical path of the optical sensor 83.

According to the above configuration, either the first light shielding plate 811 or the second light shielding plate 821 is present on the optical path of the optical sensor 83. In other words, the rotation of each of the first light shielding plate 811 and the second light shielding plate 821 can be detected individually by a single optical sensor 83. This makes it possible to accurately detect the remaining amount of toner in each of the two containers (the first container 51 and the second container 52) that supply toner to one developing device 40 with a configuration that is low cost and compact.

The first light-shielding plate 811 has a shielding portion 811a and a protrusion portion 811b.

The shielding portion 811a is disposed upstream (rearward) in the rotation direction of the first light-shielding plate 811. The shielding portion 811a is formed in a generally triangular shape that protrudes toward the upstream side in the rotation direction of the first light-shielding plate 811. When the first light-shielding plate 811 rotates, the shielding portion 811a covers the entire detection portion 83a of the optical sensor 83 at a predetermined timing (see FIG. 13).

The protrusion 811b is disposed downstream in the rotation direction of the first light-shielding plate 811 (forward in the rotation direction). The protrusion 811b is formed in a substantially triangular shape that protrudes toward the downstream in the rotation direction of the first light-shielding plate 811. In other words, the protrusion 811b protrudes toward the second light-shielding plate 821 at the point where the first light-shielding plate 811 and the second light-shielding plate 821 contact each other. The tip of the protrusion 811b has a vertex or is curved.

The second light shielding plate 821 has a shielding portion 821a and a protrusion portion 821b.

The shielding portion 821a is disposed upstream (rearward) in the rotation direction of the second light shielding plate 821. The shielding portion 821a is formed in a generally triangular shape that protrudes toward the upstream side in the rotation direction of the second light shielding plate 821. The shielding portion 821a covers the entire detection portion 83a of the optical sensor 83 at a predetermined timing when the second light shielding plate 821 rotates.

The protrusion 821b is disposed downstream in the rotation direction of the second light-shielding plate 821 (forward in the rotation direction). The protrusion 821b is formed in a substantially triangular shape that protrudes toward the downstream in the rotation direction of the second light-shielding plate 821. In other words, the protrusion 821b protrudes toward the first light-shielding plate 811 at the point where the second light-shielding plate 821 and the first light-shielding plate 811 contact each other. The tip of the protrusion 821b has a vertex or is a curved surface.

According to the above configuration, by having the protrusions 811b and 821b, it is possible to prevent the first light shielding plate 811 and the second light shielding plate 821 from becoming stuck and locked when they come into contact with each other, making it impossible to rotate. This allows the single optical sensor 83 to detect the rotation of each of the first light shielding plate 811 and the second light shielding plate 821 individually. Note that it is sufficient that at least one of the first light shielding plate 811 and the second light shielding plate 821 has the protrusions 811b and 821b, but it is preferable that both have them.

As shown in FIG. 16, the configuration of the first detection axis 81, the second detection axis 82 and the optical sensor 83 satisfies both of the following formulas (1) and (2) when the maximum value of the radius from the rotation axis of the first detection axis 81 and the second detection axis 82 to the radial outer ends of the first light shielding plate 811 and the second light shielding plate 821 is R, the distance between the rotation axes of the first detection axis 81 and the second detection axis 82 is D, the radius of the first detection axis 81 and the second detection axis 82 is r, the minimum value of the radial clearance required between the first detection axis 81 and the second detection axis 82 is c, the radial distance from the rotation axis to the farthest end of the detection unit 83a of the optical sensor 83 is R1, and the radial distance from the rotation axis to the nearest edge of the holding member 831 of the optical sensor 83 is R2. In FIG. 16, the second sensing axis 82 is described as a representative example, and for ease of explanation, only the axis portion of the first sensing axis 81 is drawn.

Formula (1) R≦Dr−c
Formula (2) R1<R<R2

With this configuration, the first light shielding plate 811 and the second light shielding plate 821 can cover the entire area of the detection section 83a of the optical sensor 83 without contacting the holding member 831 of the optical sensor 83. Therefore, it is possible to improve the detection accuracy of each of the first light shielding plate 811 and the second light shielding plate 821 by the single optical sensor 83.

Furthermore, in the configuration of the first detection axis 81, the second detection axis 82, and the optical sensor 83, it is preferable that the maximum radius R from the rotation axis of the first detection axis 81 and the second detection axis 82 to the radial outer ends of the first light shielding plate 811 and the second light shielding plate 821 satisfy both of the following formulas (3) and (4).

Formula (3) R=Drc
Formula (4) R=(R1+R2)/2

When using a small, general-purpose optical sensor, it is difficult to establish the above formula (2). However, by satisfying both the above formulas (3) and (4), it is possible to stabilize the detection accuracy of each of the first light-shielding plate 811 and the second light-shielding plate 821 by the single optical sensor 83, even when using a small, general-purpose optical sensor.

Figure 17 is an explanatory diagram relating to the counting of the number of rotations of the first detection axis 81 and the second detection axis 82 by the remaining amount detection unit 8a in Figure 2. The vertical axis of the graph shown in Figure 17 is the output value of the signal of the optical sensor 83, and the horizontal axis is time. For example, in this embodiment, the optical sensor 83 is ON in a light-blocking state in which the optical path is blocked, and is OFF in a light-transmitting state in which the light path is unblocked.

The remaining amount detection unit 8a counts the number of rotations based on the output signal Su when the optical path of the optical sensor 83 is blocked by the first light shielding plate 811 or the second light shielding plate 821, or the output signal Sd when the blocking is released. With this configuration, the first light shielding plate 811 or the second light shielding plate 821 in a stationary state is not detected, and the number of rotations is counted based on the movement of the first light shielding plate 811 and the second light shielding plate 821. This makes it possible to properly detect the amount of toner remaining in the first container 51 and the second container 52.

The above describes an embodiment of the present invention, but the scope of the present invention is not limited to this, and various modifications can be made without departing from the spirit of the invention.

For example, in the above embodiment, the image forming device 1 is a so-called tandem type image forming device for color printing that forms images of multiple colors by sequentially overlapping them, but it is not limited to this type of model. The image forming device may be a non-tandem type image forming device for color printing or an image forming device for monochrome printing.

The present invention can be used in image forming devices.

Reference Signs List 1 Image forming apparatus 8 Control unit 8a Remaining amount detection unit 20 Image forming unit 21 Photoconductor drum (image carrier)
40 Developing device 51 First container 52 Second container 60 Toner supply device 60a Junction 61 First container connection part 62 Second container connection part 63 Supply pipe 64 First vertical pipe 65 Second vertical pipe 66 First conveying pipe 67 Second conveying pipe 68 First conveying member 69 Second conveying member 70 Conveyor driving part 73 First clutch 74 Second clutch 81 First detection shaft 82 Second detection shaft 83 Optical sensor 83a Detection part 811 First light shielding plate 811b Projection part 821 Second light shielding plate 821b Projection part 831 Holding member S Paper

Claims (5)

a developing device for supplying toner to an image carrier;
a first container and a second container for accommodating the toner to be replenished to the developing device;
a toner supply device that supplies the toner from the first container and the second container to the developing device;
a remaining amount detection unit that detects the remaining amount of the toner in the first container and the second container;
Equipped with
The toner supply device is
a single supply tube connected to said developing device through which said toner flows into said developing device;
a first conveying pipe connected between the first container and the supply pipe, for conveying the toner from the first container side toward the supply pipe side;
a second conveying pipe connected between the second container and the supply pipe, for conveying the toner from the second container side toward the supply pipe side;
a first conveying member rotatably disposed within the first conveying pipe and configured to convey the toner from the first container toward the supply pipe;
a second conveying member rotatably disposed within the second conveying pipe and configured to convey the toner from the second container toward the supply pipe;
a clutch that selectively drives one of the first conveying member and the second conveying member;
a first sensing shaft coupled to the first conveying member and adapted to rotate with the first conveying member;
a second sensing shaft coupled to the second conveying member and adapted to rotate with the second conveying member;
a single optical sensor for sensing rotation about the first sensing axis and the second sensing axis;
Equipped with
the remaining amount detection unit counts the number of rotations of the first detection shaft and the second detection shaft based on an output signal from the optical sensor, and detects the remaining amount of the toner in the first container and the second container based on the number of rotations;
the first detection axis has a first light shielding plate that moves into and out of an optical path of the optical sensor;
the second detection axis has a second light shielding plate that moves into and out of the optical path of the optical sensor;
An image forming apparatus characterized in that one of the first light-shielding plate and the second light-shielding plate rotates together with the first conveying member or the second conveying member driven by the clutch and contacts the other, thereby removing the other from the optical path of the optical sensor. At least one of the first light-shielding plate and the second light-shielding plate has a protrusion protruding toward the other at a contact point between the first light-shielding plate and the second light-shielding plate,
2. The image forming apparatus according to claim 1, wherein the tip of the protrusion has a vertex or is curved. The image forming apparatus of claim 1 or 2, characterized in that when the maximum value of the radius from the rotation axis of the first detection axis and the second detection axis to the radial outer ends of the first light shielding plate and the second light shielding plate is R, the distance between the rotation axis of the first detection axis and the second detection axis is D, the radius of the first detection axis and the second detection axis is r, the minimum value of the radial clearance required between the first detection axis and the second detection axis is c, the radial distance from the rotation axis to the farthest end of the detection unit of the optical sensor is R1, and the radial distance from the rotation axis to the nearest edge of the holding member of the optical sensor is R2, both of the following formulas (1) and (2) are satisfied.
Formula (1) R≦Dr−c
Formula (2) R1<R<R2 4. The image forming apparatus according to claim 3, wherein the maximum value R of the radius satisfies both of the following expressions (3) and (4).
Formula (3) R=Drc
Formula (4) R=(R1+R2)/2 The image forming apparatus according to any one of claims 1 to 4, characterized in that the remaining amount detection unit counts the number of rotations based on the output signal when the optical path of the optical sensor is blocked by the first light-shielding plate or the second light-shielding plate, or the output signal when the blocking is released.

Images